The subject application generally relates to systems and methods for generating a channel list for a television.
In the United States, cable systems typically broadcast some digital channels “in-the-clear” and some encrypted. The encryption is used to enforce subscription to variously-priced channel packages such as, for example, via a smart-card-based conditional access mechanism, known as a CableCard. When the number of encrypted channels is sufficiently greater than the number of “in-the-clear” channels, it can be difficult for a user to find the in-the-clear channels, especially if tuning takes several seconds and there is no obvious pattern to the mix of encrypted and unencrypted channels. For instance, in an example cable system, there may be one hundred (100) digital “in-the-clear” channels, of which about half may be audio only, and over 200 digital channels that are encrypted or otherwise not viewable without a conditional access mechanism. If a user were to randomly change to a digital channel, or use the channel-up or channel-down keys to navigate to the next digital channel after scanning, the odds are better than 2:1 that the user would be left on an unwatchable channel. Furthermore, cable companies can and do change their digital channel lineups at will, in a manner that is transparent to those with CableCards or cable boxes, but aggravating to customers dependent on remembering or configuring a ring list for “in-the-clear” channels.
The systems and methods described herein remove digital channels from the ring list during a scan, if the channel does not have decodable audio or video. Consequently, the user has a much greater chance of finding “in-the-clear” channels when using channel-up or channel-down to navigate through the digital channels. The systems and methods also makes it much easier for a user without a conditional access mechanism to cope with the digital channel reassignments that are done by cable companies.
Example systems and methods of generating a television channel list described herein involve scanning virtual channels contained in a transport stream supplied to a television and determining, for each scanned virtual channel, whether that channel contains decodable video or audio content. A ring list used for tuning channels in channel up/down tuning operations is generated which contains only those scanned channels determined to have decodable video or audio content.